This is a generalisation of the commuting graph of a group, which has the elements of a group as vertices, joined by an edge if they commute see [9]. In this paper we will consider a generalisation of the graph of Herzog, Longobardi and Maj. For a finite group G we define the graph T G to be the graph whose vertices are the conjugacy.

Departament d' Algebra, Universitat de Valencia, Dr. Moliner, 50, Burjassot, Valencia, Spain e-mail: Adolfo.

- Suicide from a Global Perspective: Vulnerable Populations and Controversies (Social Issues, Justice and Status).
- On the subgroup lattice index problem in finite groups | SpringerLink.
- Listen to Your Life: Following Your Unique Path to Extraordinary Success.
- Buying Options.
- The Revolution and the Civil War in Spain;
- Keyword Search.
- Mediterranean Grilling: More Than 100 Recipes from Across the Mediterranean?

Ballester uv. Cossey anu. We characterise those groups G for which F G is complete. Permutability, like normality, is not a transitive relation in general.

**see**

## Groups satisfying certain rank conditions | Dixon | Algebra and Discrete Mathematics

According to a classical result of Ore [10] permutable subgroups of finite groups are subnormal. Hence a finite group is a PT-group if and only if every subnormal subgroup is permutable. Suppose that G is a soluble PT-group. In the other direction, we argue by induction on the order of G. We begin by showing that G is a soluble PT-group if G has at least two minimal normal subgroups. Thus we suppose that all minimal normal subgroups have the same prime order p. Thus all p-chief factors are G-isomorphic.

Therefore G is supersoluble and all chief factors of the same order are G-isomorphic. If the p-chief factors are central, then G is a p-group with all proper quotients modular and so is itself modular, since by Theorem of Longobardi [8] such a group must have a unique minimal normal subgroup. Assume now that MN is a Sylow p-subgroup of G. Consequently M and N are G-isomorphic. We now suppose that G has a unique minimal normal subgroup N. Let p and q be different primes dividing the order of Si and let xi and yi be elements of Si of orders p and q, respectively.

Then xi.. The projection of xi A result of Abe and Iiyori [i] shows that this is impossible. Consequently N is a p-group for some prime p. Let Q be a cyclic normal subgroup of M. It now follows that every element of F acts as a power automorphism on N and hence F acts as a power automorphism group on N. Since power automorphisms are central in the power automorphism group of N [5, Theorem 2. Thus M is a nilpotent modular group. In particular M is a p'-group.

Let Q be a non-abelian Sylow q-subgroup of M. By Iwasawa's Theorem [ii, Theorem 2.

### About De Gruyter

In both cases every cyclic subgroup of Qo is normal in Q and hence in M. Let U be a cyclic subgroup of N and let R cyclic subgroup of Qo. By hypothesis, there exits an element a e M such that RUa is subgroup.

This implies that Q normalises U and Q acts as power automorphisms on N. It now follows that M acts as power automorphisms on N and so N is a cyclic group of order p and M is cyclic of order dividing p — i and G is clearly a PT-group. Now suppose that N is contained in the Frattini subgroup of G. Assume that G is not modular. By the Theorem of Longobardi [8] either G is the central product of a subgroup P isomorphic to M p and another subgroup or G is isomorphic to.

In the first case it is clear that if P is generated by a and b of order p no conjugate of a will commute with b and hence will not permute with b. Since w centralises b and b has order at least 4, w acts as universal power automorphism on H by a theorem of Napolitani [11, Theorem 2. Thus G cannot be nilpotent. Then there exists a p'-subgroup D of G complementing E in G.

It follows that D is cyclic of order dividing p — 1.

## Subscribe to RSS

Assume that Ep is not trivial. Chapter 2 Modular lattices and abelian groups.

Chapter 6 Projectivities and normal structure of infinite groups. Chapter 7 Classes of groups and their projectivities.

- Invitation to Positive Psychology: Research and Tools for the Professional.
- GAP (PERMUT) - References;
- Two for Sorrow: A New Mystery Featuring Josephine Tey (Josephine Tey Mysteries)?
- Limb lengthening and reconstructive surgery.
- Complemented group!
- Synchrotron Radiation Research: Advances in Surface and Interface Science!

Chapter 3 Complements and special elements in the subgroup lattice of a group. Chapter 4 Projectivities and arithmetic structure of finite groups. Chapter 5 Projectivities and normal structure of finite groups. Chapter 8 Dualities of subgroup lattices. Chapter 9 Further lattices. Index of Names. Index of Subjects.